1. Field of the Invention
This invention relates to bottle closures in general and more specifically to an improved twist open/close cap having a stop wedge cooperative with a stop wedge on the neck of a container for dispensing rate control and preventing removal of the outer cap. The present invention provides multiple fluid seals.
2. Description of the Prior Art
The use of twist open/close container closures are well known and have been in commercial use for some time. One basic characteristic common to all these closures is the ability to dispense the container contents without removing the outer cap. This is generally accomplished by means of cooperative threads or ramp systems designed to raise an outer cap releasing the sealing engagement between a central plug and an aperture in the outer cap. Unfortunately many of the outer caps of these closures contain no means for alerting the user when the dispensing aperture is in the full open position. Without some form of stopping means, the outer cap can be inadvertently removed negating the convenience of the twist open/close caps. Stop wedges or lugs which prevent overturning the cap upwardly or downwardly are sometimes used. Subtle differences is design, however, can create major differences in cap efficiency. These subtle design differences can also be involved in the cost effectiveness of the manufacturing process as well as causing major changes in the convenience of use and ability of the cap to seal well.
To uncover past art pertaining to twist open/close caps utilizing step means designed to limit rotation of the outer cap and prevent removal or disassembly of the cap components, a search was conducted in the following classes and subclasses:
222/521, 542, 521, and 494.
Although a wide variety of past art twist open/close caps were produced by the search, none provided a combination of stop blocks (and method) and multiple sealing in the same manner my cap does.
Those patents which seemed to describe caps having mechanics most representative to my device included:
U.S. Pat. No. 2,542,350, granted to E. H. Paulsen on Feb. 20, 1951, for snap-on dispensing closure for collapsible tubes having a positioning lug for limiting the revolution of the outer cap when opening the dispensing cap. To snap the Paulsen cap onto the tube neck threads, it was necessary to provide the lower portion of the cap skirt with longitudinal slits to gain resilience for permitting the cap to be snapped in place over the threads of the tube neck. Slitting the cap weakens the cap structure as well as provides a bacterial entrance into the tube neck. With modern plastic materials available for manufacturing today, the slits in the cap skirt would add needless cost to the tooling and manufacturing of a similar cap. Also, the central closure plug structure is inherent to the tube or container making the cap incompatible with typical bottle blow mold manufacturing. That particular container manufactured as a tube would normally not have a flat supporting bottom surface. This proves to limit the use of this closure to dispensing the more viscous types of materials such as toothpaste due to the fact that the container will more that likely be positioned on the side, resulting in increased incidence of leakage of a more fluid material.
The Porter patent, U.S. Pat. No. 3,175,741, dated Mar. 30, 1965, describes a "Closure And Dispensing Cap For The Neck Of a Container." A stop for limiting rotation of the outer cap utilizing wedge shaped vertical stops are used to limit the revolution of the outer cap to about one 360 degree rotation. Removal of the outer cap is prevented by the abutment of the wedge shaped stops when in the full opened position. The outer cap is structured with a considerably concaved circular top portion having a dispensing hole in the bottom of the concave surface area, a structure allowing for a short turn to place the plug securely in the outer cap aperture. This cap would have a limited use as directive dispensing of materials from the container would appear difficult. Deeply concaved dispensing tops have been shown to be ineffective in directing the flow of the materials accurately and usually leave a large puddle of the material in the concave dish. Also, the inner or base portion of the cap having the closure tip is intrinsic with the container making it incompatible with standard modern plastic bottle blow molding processes which require an open bottle neck.
The Stull patent, U.S. Pat. No. 3,216,630, shows a narrow tipped cap using two ramp style stop blocks to limit cap turning. These stop blocks function to limit rotation of the outer cap past the fully closed position, thereby preventing disengagement or overriding of the cooperating threads of the two cap sections. Stop blocks positioned for limiting the turning of the outer cap in the closing operation have been found to not to be an advantage. The sealing surfaces of the inner and outer cap structure must meet together with a degree of force in order to seal properly. This meeting of the sealing surfaces is marked by a noticeable increase in the resistance to turning. A user of a similar cap without stop blocks to restrict turning of the outer cap in the closing operation would be very unlikely to strip or cause the threads to override and would have a greater choice in the degree of tightness of the mating sealing surfaces. Stop blocks sometimes prevent adequate cap sealing which can cause leaking problems particularly undesirable during shipping.
Other patents issued to M. B. Stull include U.S. Pat. No. 3,339,773, dated Sept. 5, 1967; U.S. Pat. No. 3,406,880, dated Oct. 22, 1968: and U.S. Pat. No. 3,407,967, dated Oct. 29, 1968. All show variations in twist open/close caps with close sensors and limiting stops. These other Stull patents mostly illustrate caps using narrow projecting nozzles which require special packaging, are not readily stackable, have limited aperture sizing, and appear to seal only by cap contact with the container neck threads.
My invention overcomes the disadvantages seen in the past art patents by providing a more positive unrestricted sealing of the flow plug. Also, by carefully positioning cap rotational stop wedges in manufacturing, my invention provides the user virtual foolproof means to readily open the dispensing aperture to a predetermined size for a controlled optimal flow rate for the specific viscosity of material to be dispensed.